The current technique of insulating low voltage power cables and telecommunications cables as used by practically all cable manufacturers, is the extrusion technique which consists in insulating an electrical conductor coming from a wire-drawing machine by passing it through an extruder.
However, the speed at which a conductor can pass through an extruder is limited, and consequently the speed at which cable can be manufactured is limited.
The present invention makes it possible to do without the extruder, and the cable manufacturing speed is thus the speed at which the wire-drawing machine can deliver wire. For example, an extruder limits the speed to about 10 m/s (meters per second), while a wire-drawing machine can reach a speed of about 40 m/s.
The present invention also makes it possible to insulate an electrical conductor in a single operation directly at the outlet from the wire-drawing machine by means of a cellular insulant having good mechanical properties unlike cellular insulants currently obtained by extrusion which are soft and likely to melt.